// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CC_LAYERS_SCROLLBAR_LAYER_IMPL_BASE_H_
#define CC_LAYERS_SCROLLBAR_LAYER_IMPL_BASE_H_

#include "base/macros.h"
#include "cc/base/cc_export.h"
#include "cc/input/scrollbar.h"
#include "cc/layers/layer.h"
#include "cc/layers/layer_impl.h"

namespace cc {

class LayerTreeImpl;

class CC_EXPORT ScrollbarLayerImplBase : public LayerImpl {
public:
    int ScrollLayerId() const { return scroll_layer_id_; }

    void SetScrollLayerId(int scroll_layer_id);

    float current_pos() const { return current_pos_; }
    bool SetCurrentPos(float current_pos);
    bool SetClipLayerLength(float clip_layer_length);
    bool SetScrollLayerLength(float scroll_layer_length);
    bool SetVerticalAdjust(float vertical_adjust);

    float clip_layer_length() const { return clip_layer_length_; }
    float scroll_layer_length() const { return scroll_layer_length_; }
    float vertical_adjust() const { return vertical_adjust_; }

    bool is_overlay_scrollbar() const { return is_overlay_scrollbar_; }
    void set_is_overlay_scrollbar(bool is_overlay)
    {
        is_overlay_scrollbar_ = is_overlay;
    }

    ScrollbarOrientation orientation() const { return orientation_; }
    bool is_left_side_vertical_scrollbar()
    {
        return is_left_side_vertical_scrollbar_;
    }

    bool CanScrollOrientation() const;

    void PushPropertiesTo(LayerImpl* layer) override;
    ScrollbarLayerImplBase* ToScrollbarLayer() override;

    // Thumb quad rect in layer space.
    virtual gfx::Rect ComputeThumbQuadRect() const;

    float thumb_thickness_scale_factor()
    {
        return thumb_thickness_scale_factor_;
    }
    bool SetThumbThicknessScaleFactor(float thumb_thickness_scale_factor);

protected:
    ScrollbarLayerImplBase(LayerTreeImpl* tree_impl,
        int id,
        ScrollbarOrientation orientation,
        bool is_left_side_vertical_scrollbar,
        bool is_overlay);
    ~ScrollbarLayerImplBase() override;

    virtual int ThumbThickness() const = 0;
    virtual int ThumbLength() const = 0;
    virtual float TrackLength() const = 0;
    virtual int TrackStart() const = 0;
    // Indicates whether the thumb length can be changed without going back to the
    // main thread.
    virtual bool IsThumbResizable() const = 0;

private:
    int scroll_layer_id_;
    bool is_overlay_scrollbar_;

    float thumb_thickness_scale_factor_;
    float current_pos_;
    float clip_layer_length_;
    float scroll_layer_length_;
    ScrollbarOrientation orientation_;
    bool is_left_side_vertical_scrollbar_;

    // Difference between the clip layer's height and the visible viewport
    // height (which may differ in the presence of top-controls hiding).
    float vertical_adjust_;

    DISALLOW_COPY_AND_ASSIGN(ScrollbarLayerImplBase);
};

typedef std::set<ScrollbarLayerImplBase*> ScrollbarSet;

} // namespace cc

#endif // CC_LAYERS_SCROLLBAR_LAYER_IMPL_BASE_H_
